Self fill differential collar



Aug. 5, 1958 c. PITTMAN 2,846,015

SELF FILL DIFFERENTIAL COLLAR v Filed lay 10, 1957 2 Sheets-Sheet 1 FILL UP COLLAR I I, I: CASING 'f- IO E l /E'| I g 4 i/ -FLoAT COLLAR 4% I: I it; 3/ EM 5' ag DRILLING MUD ii i CASING Z IO 5 i FLOAT SHOE INVENTOR. FORREST c. PITTMAN, FIG. I. BY

ATTORNEY.

Aug. 5, 1958 F. c. PITTMAN 2,846,015 SELF FILL-DIFFERENTIAL COLLAR Filed May 10, 1957 2 Sheets-Sheet 2 FIG. 2.' FIG.4. .FIG. 5.

54 Fl G. 3. ZNVENTOR.

FORREST c. PITTMAN,

ATTOR NEY.

Unite tates ice SELF FILL DIFFERENTIAL COLLAR Forrest C. Pittman, Duncan, burton Oil Well Cementing a corporation of Delaware Application May 10, 1957, Serial No. 658,334 4 Claims. (Cl. 166-224) Okla, assignor to Halli- Company, Duncan, {)ltla,

and difliculties have been encountered in lowering such casing through the well fluids, as the depths of dn'lled wells have increased.

A common practice, still employed, is to fill the casing manually with the drilling fluids as it is being lowered into the well. To overcome the obvious difficulties of such manual filling practices, various so-called automatic devices have been developed. These devices are gen erally attached to the bottom of a string of casing and are modifications of the conventional float shoes or float collars. Such devices are of necessity complicated in design and operation, and in many instances do not operate too successfully. Such devices employ a valving means to control the flow of fluids from the bore hole into the casing, and they must also have another valving means for the discharge of fluids into the bore hole in order to place the cement around the casing. Some examples of such devices attached to the bottom of a string of easing are found in the following United States Patents: 2,713,870, 2,718,265, 2,713,914, 2,724,443, 2,717,647, 2,717,648, and 2,717,649.

The first departure from the devices of the prior art that is known to this applicant is that of Maly et al., in patent application Serial No. 546,620, filed November 14, 1955. In the Maly, et a1. application a device separate from the conventional float shoe or float collar is employed, which results in satisfactory, reliable, and controlled filling of a well casing. The filling of the casingis effected through side ports in the tool rather than through the bottom of the string of casing.

One object of this invention is to provide a novel improvement of the casing fill up device disclosed in the above Maly et al., application.

It is another object of this invention to provide a means to close the tool, if it becomes necessary to float the easing into the bore hole.

It is still another object of this invention to provide a means to establish circulation at any time during the lowering of the easing into the bore hole without aflecting subsequent operations of the tool and without losing circulation through the ports provided in the tool.

Other objects and advantages of the invention will become apparent from the following description, when taken in connection with the accompanying drawing in which:

Figure 1 is a diagrammatic view in elevation showing a casing provided with a conventional float shoe and the tool of the invention being lowered in a well bore.

Figure 2 is a longitudinal cross sectional view of the tool in the closed position.

Figure 3 is a cross sectional view taken along A-A of Figure 2.

Figure 4 is a longitudinal cross sectional view of the tool opened so that fluids will enter the casing.

Figure 5 is a longitudinal cross sectional view of the tool showing the permanent closure of the ports.

Referring to the drawings in detail, Figure 1 illustrates a string of well casing 10 being lowered into a well bore 12. Assembled to the lower end of the casing 10 is a conventional float shoe 14. Placed above the float shoe 14, at any position desired in the string of casing 10, is the fill up tool 16 of the invention.

The housing 18 of the tool 16 is adapted at 20 and 22 to be placed between two joints of the casing 10. If desired, the housing 18 may be connected at 22 directly to the float shoe 14 by means of an adapter coupling 23 and at 20 to the casing 10. At least two transverse ports 24 are provided in the housing 18.

A hollow valve body 38 of drillable material, such as aluminum, is positioned inside the housing 18. The hollow portions are designated by the numeral 42. Fitted around the outside of the lower portion of the valve body 38 is a sleeve 26 with ports 24a. Horizontal fluid passageways 2412 are provided in the valve body 38. As shown in Figure 2 shear pins 28 are provided to hold the sleeve 26 and the valve body 38 in temporary fixed relationship to the housing 13 and to hold the ports 24 and 24a in communication with the fluid passageways 24b.

The sleeve 26 is provided with a groove 30 in which is placed a snap ring 32. The snap ring 32 is adapted to engage a groove 34 in the housing 18 when the sleeve 26 is in the position shown in Figure 5. Leakage of fluid between the housing 18 and the sleeve 26 is prevented by O-rings 36.

The sleeve 26 is shown as fitted into a recess in the valve body 38 and is of a different material. The sleeve 26 could be constructed as an integral part of the valve body 38 without departing from the spirit of the invention. However, the preferred embodiment is shown in the drawing. A vertical conduit 40 is provided to connect the fluid passageway 24b with the hollow portions 42. A valve means 44 is positioned in a hollow cylinder 40a defined by the walls 41 of the valve body 38. At the point where the horizontal fluid passageway 24b and the vertical conduit 41) intersect, the interior of the valve body 38 is machined to provide a seat 46. The top 64 of the valve body 38 has a shear ring 66 inserted therein.

The valve means 44 consists of several coacting elements. A piston 48 of clrillable material has a rubberlike plug 58 molded to its upper end. A rounded portion 52 of the nose 53 of the rubber like plug 50 has a smaller diameter than the base 54, which provides a bearing surface for the application of pressure. At the base 49 of the piston 48 is a coil spring 56 with a hollow spring retainer 58 positioned therein. The spring 56 and its retainer 58 are held in the position shown in the drawing by a retaining ring 60, which fits into a groove 62 of the valve body 38. An O-ring 68 prevents fluid leakage between the piston 48 and the portion of valve body 38 defined by the conduit 40a.

An illustration of the operation and coaction of the elements of the invention is as follows:

The tool 16 is assembled in the string of well casing 10 at any place above the conventional float shoe 14. It a float collar is employed in addition to the float shoe 14, the tool is placed above such float collar. The assembly is then lowered in the bore hole 12, which contains drilling fluid. As the assembly is lowered additional joints of well casing 10 are added. The valve means 44 of the tool 16 is in the position shown in Figure 2 of the drawing, since the spring 56 exerts force on the piston 48, whereby the nose 52 of the rubber like plug 50 firmly engages the seat 46 of the valve body 38. The

valve in the float shoe 14 remains in the closed position, and the interior of the casing 10 remains empty until the embodiment of the invention begins to function.

The fluid in the bore hole 12 enters the ports 24 as the assembly is lowered and exerts a pressure on the base 54 of the rubber like plug 50; such pressure at any depth is of course that of the hydrostatic head of the fluid in the bore hole 12. The spring 56 is of such strength that it will overbalance a predetermined pressure exerted by the hydrostatic head of the fluid. By way of example in illustrating the invention, the spring 56 will maintain the valve means 44 in a closed position up to a pressure of 80 pounds per square inch (p. s. i.). When the pressure exerted by the hydrostatic head of the fluid on the base 54 of the rubber like plug 50 approaches 80 p. s. i., the piston 48 moves downwardly and starts to compress the spring 56. The nose 52 of the rubber like plug 50 separates from the seat 46 and the fluid, then passes around and enters the vertical conduit 40. At this point the pressure of the hydrostatic head of the fluid is acting on the entire surface of the rubber like plug 50, and such increase in pressure snaps the piston 48 downwardly, whereby the valve means 44 assumes the open position as shown in Figure 4 of the drawing.

Fluid enters the casing 10 through the ports 24, conduit 40, and the hollow portions 42. The fluid inside the casing 10 will exert a pressure due to its hydrostatic head. The hydrostatic head of the fluid outside the casing 10 is greater than that of the fluid inside. Such difference is commonly termed the diflerential pressure. Depending upon the strength of the spring 56, fluid will continue to enter the casing 10. Before the casing 1% completely fills and overflows the system is so adjusted, so that the valve means 44 will close the passageway 24b and thereby prevent the entry of additional fluids. Again as an illustration, the spring 56 is so designed that at about a differential pressure of 60 p. s. i., it starts pushing the piston 48 upwardly. As the rubber-like plug 50 moves toward the seat 46, less area of the nose 5'2 is subjected to the fluid pressure from the bore hole 12, and thus the valve means 44 snaps shut and the system again assumes the position as shown in Figure 2 of the drawing. When the differential pressure reaches about 80 p. s. i., the system again opens as described above and the fluid enters the casing 10. It is thus seen that the unique arrangement and construction provide a means for self or automatic filling of a well casing as it is lowered into a bore hole to a desired depth. It is to be noted that the valve means 44 normally has only two positions, either fully closed or fully opened. The intermediate position is barely perceptible due to the pressure exerted by the fluid and the spring 56. Such a feature is advantageous in that it prevents clogging the ports 24 and 24a and the passageway 24b.

The next step in the operation is to cement the casing 10 in the bore hole 12, by any of the conventional methods employed in the art. After the cement is displaced it is desirable to seal ofl permanently the ports 24. As is known in the cementing art, a solid top plug'(not shown) is placed on top of the cement in order to displace the cement in the casing 10 out through the float shoe 14 at the bottom of the casing 10. In the embodiment of the invention such a plug will come to rest on the top 64 of the valve body 38. Increased pressure applied at the surface to the displacing fluid is transmitted through the top 64 to the valve body 38 and shears pins 28 between the housing 18 and the sleeve 26. The sleeve 26 and the valve body 38 move downwardly until the snap ring 32 engages the groove 34 in the housing 18, and the ports 24a of the sleeve 26 are moved out of communication with the ports 24 of the housing 18.

The cement sets up around the outside of the casing to and inside the casing 10 to the top 64 of the valve '12, and hence has a tendency to float.

4 body 38. If desired the cement, the valve body 38 and the valve means 44 are then drilled out.

The above description of the operation of the invention is that of the normal situation in which no difficulties are encountered in lowering the casing 10 into the bore hole 12.

The present invention is adapted also to overcome some common difficulties encountered in lowering casing through fluid into a well bore.

it occasionally happens that after the casing 10 is lowered part of the way in the well bore 12, it becomes necessary to circulate before the casing 10 can be lowered any further, due to some obstruction in the well bore 12. By circulate" it is meant to pump the drilling fluid down through the casing 10, out the float shoe 14 at the bottom, and up to the surface through the well bore 12 and outside the casing 10. With the valve means 44 in the open position of Figure 4, circulation could not be accomplished as the fluids would tend to be forced out into the well bore 12 through the passageway 24b and the ports 24a and 24.

Before the circulation operation is commenced, the passageway 24b would be automatically closed by the valve means 44, as is described in the operation above, since the differential pressure would not be sufficient to overcome the force exerted by the spring 56. During circulation the valve means 44 is maintained in the closed position, as shown in Figure 2. The circulating fluid passes down through the casing 10 by means of pump pressure exerted at the surface. The fluid passes around the valve means 44 and the tubular passageway 24b through the hollow portions 42. The fluid in the conduit 4% acts on the nose 53 of the rubber like plug 50, which would tend to move the valve means 44 downwardly and hence unseat it. However, the pressure of the fluid in the casing 10 also acts on the base 49 of the piston 48. The base 49 is so constructed that it is of a larger cross sectional area than that of the nose 53 of the rubber like plug 50. Therefore, the pressure acting upwardly on the base 49 is greater than that acting downwardly on the nose 53, so the valve means 44 is aided by the spring 56 will remain firmly closed. As soon as the circulation operation is completed the tool 16 operates as has been described above.

Sometimes after the casing 10 has been lowered to a certain depth, and fluid added as described above, it is desirable to float the casing 10 the remainder of the distance in the bore hole 12. By floating it is understood in the art that the casing 10, empty or partially filled with fluids, is buoyant in the fluids in the well bore In this event, it is necessary to permanently close off the ports 24 in the housing 18. This is accomplished in a similar manner as described above after the cementing operation. Instead of the top cementing plug, a ball (not shown) is dropped through the casing 10 and lands on the shear ring 66 in the valve body 38. Suflicient pressure is applied to the ball so that the pins 28 shear, whereby the sleeve 26 and the valve body 38 move down and close off the ports 24 as described above. In order to perform the cementing operation the ball must be removed. This is accomplished by additional pressure on the ball, which breaks the shear ring 66, allowing the ball to fall into the space 42, where it will not obstruct flow through the bottom of the casing during the cementing operation.

From the foregoing description in connection with the various figures of the drawing, it is seen that this invention provides a novel automatic means to fill a well casing as it is lowered into a well bore and that such device provides a solution in the event certain common dithculties are encountered.

Although the invention has been described in terms of a specific embodiment, it should be understood that this was by way of illustration only and that the invention is not limited thereto. Accordingly, modifications of the vertical fluid passageways, said horizontal fluid passageway being in temporary communication with said ports in said housing, shearable means adapted to hold said valve body in temporary fixed relationship to said housing, said shearable means being adapted to hold said ports and said horizontal fluid passageways in temporary 1 communication, and valve means in said valve body adapted to permit the entry of fluid and to exclude the entry of fluid into said conduit as it is being lowered into a bell bore, said valve means being operated by the differential pressure.

2. An improved device for automatically filling with fluid a conduit lowered into a well bore, comprising, in combination, a housing connected to said conduit, said housing having ports, a hollow valve body fitted inside said housing, said valve body having connecting horizontal and vertical fluid passageways, a sleeve disposed inside said housing and disposed around said valve body, said sleeve having ports in temporary communication with the ports in said housing, said sleeve being adapted to close the ports in said housing, shearable means adapted to hold said sleeve and said valve body in temporary fixed relationship to said housing, said shearable means being adapted to hold said ports and said horizontal fluid passageways in temporary communication, and valve means in said valve body adapted to control automatically the flow of fluids through said ports and said fluid passageways, as said conduit is being lowered into a well bore, said valve means being operated automatically as the fluid pressures inside said conduit and outside said conduit vary.

3. A11 improved device for automatically filling with fluid a conduit lowered into a well bore, comprising, in combination, a housing connected to said conduit, said housing having transverse ports, a hollow valve body fitted inside said housing, said valve body having connecting horizontal and vertical fluid passageways, a sleeve having transverse ports fitted in a recess in said valve body, shearable means adapted to hold said sleeve and said valve body in temporary fixed relationship to said housing, said shearable means being adapted to hold said transverse ports and said horizontal fluid passage- Ways in temporary communication, and valve means in said valve body adapted to automatically close said horizontal and vertical fluid passageways to the flow of fluids from the well bore into the said conduit by the action of differential pressure as said conduit is being lowered into a well bore.

4. An improved device for automatically filling with fluid a conduit lowered into a well bore, comprising, in combination, a housing connected to said conduit, said housing having transverse ports, a hollow valve body fitted inside said housing, said valve body having connecting horizontal and vertical fluid passageways, a sleeve having transverse ports fitted in a recess in said valve body, shearable means adapted to hold said sleeve and said valve body in temporary fixed relationship to said housing, said shearable means being adapted to hold said transverse ports and said horizontal fluid passageways in temporary communication, and valve means in said valve body adapted to automatically open said horizontal and vertical passageways to the flow of fluids from the well bore into the said conduit by the action of diiferential pressure, as said conduit is being lowered into a well bore.

References Cited in the file of this patent UNITED STATES PATENTS 

